1. Field of the Invention
The present invention relates to a backlight unit for use in, for example, a liquid crystal display apparatus, and a liquid crystal module incorporating the backlight unit.
2. Description of the Background Art
Conventionally, liquid crystal display apparatuses, in which a liquid crystal module is surrounded by a housing, have been known. The liquid crystal module includes a liquid crystal panel and a backlight unit provided behind the liquid crystal panel. Between the liquid crystal panel and the backlight unit, a diffusing plate and optical sheets are provided. Light radiated from the backlight unit and light reflected from a reflector are diffused by the diffusing plate and the optical sheets so that brightness distribution is made uniform, and then emitted to a liquid-crystal-panel side.
Japanese Laid-Open Patent Publication No. 2006-185908 (Patent Literature 1) discloses a configuration of such a liquid crystal display apparatus. In a liquid crystal display apparatus disclosed in FIG. 10 of Patent Literature 1, a rear surface (on a light-source side) of a diffuser sheet is supported by conical diffusing plate support members projected from an inner front surface of a bottom surface of the housing. These diffusing plate support members support the diffusing plate, thereby suppressing deterioration of optical characteristics, which is caused by deflection of the diffusing plate.
Also, in order to improve the optical characteristics of the liquid crystal display apparatus as described above, there is a case where an optical pattern is provided on both surfaces of the diffusing plate. Japanese Laid-Open Patent Publication No. 2008-243637 (Patent Literature 2) discloses in FIG. 2 thereof a diffusing plate in which substantially semicircular portions are provided on a front surface (on a liquid-crystal-panel side) of the diffusing plate, and a matte surface having substantially arc shapes or a slight curve shape is provided on a rear surface (the light-source side) of the diffusing plate.
Even if an optical pattern is provided on both surfaces of a diffusing plate as disclosed in Patent Literature 2, diffusing plate support members are required as disclosed in Patent Literature 1 to prevent the deflection of the diffusing plate. Portions (on a rear surface of the diffusing plate) against which the diffusing plate support members abut are required to stably support the diffusing plate.